Portable-drill attachment



Dee. 1 1,1923.'- 1,477,439

, H. W. GRAU PORTABLE DRILL ATTACHMENT Filed Se1ot. 15. 1921 M 1 Ex Patented Dec. ll, 1923.

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HENRY WALTER GRAU, or LONG GREEN, MARYLAND.

PORTABLE-'DRILL ATTACHMENT.

"Application filed September 15, 1921. Serial No. 500,743.

To all wkom it'may concern:

'Be-'it"known"that IfHnNRY W. GRAU, a citizen of-the United States, residing at Long Green, in the *county of Baltimore "andState of'Maryl-and, have invented certainhew a-nd useful Improvements in Port able-Drill "Attachments, of which the following isaspecifi'cati'on. I

This invention ;rela;tes to attachments for portable"drills whereby.;.the drill may be readily handled 'and'appliedto the work by :t-he operator,-andwhereby the work maybe fed to -the tlrill,-or the drill tothe work. In carrying out, the invention, I provide a draw rod which {is -slidably mounted with respect to the drillc'asiiigandqorovided with a foot-whichextends in advance of the drill :bit. This -fo0t is normally pressed away from the drill :bitby ,a spring and is movable-toward, the bit by a lever which is detachably interchangeably connected to the drill casing and the draw'rod in such manner that the handle of the lever may be extended at'one side or the other of the casing, as desired, to suit "the surroundings llIl which the drilling work is to be done. This lever, in conjunction with an interchangeable handpiece, which may be located at one "side orthe other of the drill casing, afiords a convenient me'ansffor lifting'and holding the drill as well as a means for moving the draw rod relatively to the drill to feed the work to the drill, or the drill to the work. The invention comprises other-featuresof construction, the details of which will be plainfrom' the following specification, take'nfin connection wit-h the accompanying drawing, in which, n

Fig. 1 is a side elevationof a drill provided with my improvements;

Fig. 2 is a top plan View of the same;

Fig. 3 is a View similar to that in Fig. 1, but showing the operating lever in the reverse-position; Y I

Fig. 4 is a top plan view ofFig. 3; and,

Fig. 5 is a detailot one end of the drill, inverted, showing; an attachment which may be. applied to the draw rod as a rest wlien'boring upwardly, j

Referring to thedrawing, A' represents the drill, the casinga of which is provided with short laterally projecting ears or fbr'ackets xa' at thetop and'ibottom. These brackets are bored with alined openings within .the upper and form guides fora draw rod 1, which extends parallel with the longitudinal axis of the drill spindle 2. 'A bracket 3 is removably secured to the lower end ofithe draw rod by a set screw 3, and this bracket is angularly adjustable about the axis of the rod. The bracket projects laterally from the rod and has an elongated vertical slot or opening adapted to receive the arm 4 of an L-shaped foot. piece 4;. The bracket holds this arm'of the foot piece parallel with the axis of the "drill, while the other-arm l 'extends a't'ri ght angles'to the axis of the drill. The bracket carries clampingmemberio by whichthe arm 4 can be clamped to the bracket and held in any desired position of adjustment with respect to the draw bar, or the foot can be removed when desired,"by releasing the clamping member. The draw rod is prevented from turning iby a key 7, fitting guide a and engaging an extended guide slot in the rod.

A compression spring 8, surrounding the draw rod and interposed between the upper guide a,'and a collar 9on the rod normally tends to press the rod in the direction 'to move the foot away from the drill bit. For moving the draw'rod in the opposite direction, I provide a link 10, which is pivoted to the collar by a bolt 11, which extends through the collar andenga'ges the rod, and a forked lever I), which may be connected in different ways to the drill casing and link, as shown in the drawing. The lever comprises a handle portion 12 and two arms 12 and '12", the latter having near their free ends alined openings 13, and at equal distances from said openings 'other'alined openings 14'. The drill casing the drill casing by passing'th'e trunnions through the openings -14, the free end of one arm -12 of-the lever will be connected to the link 10 by a pivot pin 16, passing through the opening 13 in said arm, while .the', opening -13-in .the opposite arm will have no function. When the lever is arranged in the reverse position with respect to the drill casing, as shown in Figs. 3 and 4c, the trunnions will pass through the end openings in both arms and the link will be connected to one oi. the arms 12 by passing of the pivot pin 16 through the opening l t in said arm. Theeopening lt in the other arm will thenhave no function.

The drill casing is provided with internally threaded bosses 17, at diametrical-.

ly' opposite points, the, axis of these openings being in the plane of the handle 12 of the lever and substantially at right angles to the axis of the trunnions 15. A hand piece a, threaded at one end, is adapted to fit interchangeably into the openings in these bosses. l/Vhen the hand lever is connected so as to project at one side of the casing, the hand piece 0 will be inserted in the post at the opposite side of the casing so that the operator standing at the side of the drill may hold it with both hands, one hand gripping the hand piece and the other holding the lever. For'working in some situations, it may be desirable to leave the hand piece 0 off of the casing and use a hand gripcl, which may be attached to the end of the casing.

In the operation of the drill, the lever will be connected to project at one side or the other of the casing, as may be found most expedient in applying the drill to the work. It the hand'piece 0 is used, the operator takes hold of this or of the grip d with one hand, and with the other hand grips the free end of the lever. The foot piece which is normally pressed away from the drill bit by the spring is then placed back of the work to and the drill is placed at the point where the hole is to be bored, and if the lever is connected, as shown in Figs. 1 and 2, the handle of the lever is pressed downwardly, or in the direction of the work, to move the draw rod and foot against the work. Continued movement of the lever will cause the draw rod and drill casing to move relatively to one another to feed the work to the drill, or the drill to the work. If the lever is connected as shown in Figs. at and 5, an upward pull on the lever will be required to cause relative movement of the draw rod and drill. hen the lever is released, the compression spring 8 moves the draw rod in the direction to carry the foot away from the work and causes the lever to be returned to its initial position. The clamping engagement of the foot against the work helps to steady the drill and insures greater accuracy in boring than where the drill is merely held'by the operator and fed to the work by the direct pressure of the operators body.

In the operation of a portable drill, which is without a supporting stand, the

operator must support the drill, hold it against turning about its axis when the bit is in engagement with the work,.and also press the drill to the work. .By means of my invention, the lever pivoted to the drill casing, and opposed to one of the grips or handles usually. furnished as a part of the drill equipment, serves as a means for handling and supporting the drill, as a means for resisting the tendency of the drill to turn about the 'axis of its spindle, and also as a means for pressing the drill toward the work, or the work toward the. drill.

By arranging the draw rod as close as practicable to the drill casing, and makingit relatively short, a saving in weight is attained by shortening the guides or hearings in which the rod slides, and the weight and length of the forked arms of the operating lever is decreased, with increase of leverage. It is to be notedthat the draw rod is out of line with the handles 0, and close to the plane of one of the forked arms of the lever. The detachable foot, 'ofiset from the draw rod by the bracket 3, provides lateral clearance for the work, and permits of the draw rod being placed close to the drill casing and made relatively short. When the drill is used as a breast drill, the foot may beremoved, thus further lightening the drill, or

it nay be swung about the axis of the rod,

outof the way'of the drill and the work, by

loosening the set screw 3*.

Where it is desired'to' bore in an upward direction, an arm 18, Fig. 5' may be applied to the end of the draw rod, opposite the foot, to support the drill against a 'floor or' other object. This arm may be secured to the rod by a clampin'g screw 19, and a conical projection 18 on the arm, which bears against the floor or support, is in line with the axis of the drill spindle and serves as a means for causing the pressure onthe drill to be applied axially of the spindle.

lVhat I claim is:

1. The combination with a portable drill having a casing, of a hand lever having parallel arms pivoted to opposite sides of the casing, a draw rod slidably mounted on said casing adjacent the plane of one of said arms, and a link connecting said rod with the latter arm whereby the pivoting may be interchangeable between. the casing and the ink.

2. The combination with a portable drill having a casing, said casing having means at its opposite sides for receiving a detachahaving a casing, of a draw rod slidably mounted close to said casing and extending parallel with the axis of the drill spin dle, a bracket projecting laterally from the lower end of said draw rod, an L-shaped foot having an arm adjustably secured in the outer part of said bracket and extending parallel with the draw rod, and a lever pivoted to the side of the drill casing and connected to said rod for moving the latter 10 relatively to the drill.

In testimony whereof I affix my signature.

' HENRY WALTER GRAU. 

